The present invention pertains to a razor blade unit for a razor.
Conventional razor blade units for wet shaving usually consist of two frame parts, where the slide strip is arranged on one of the frame parts and the foam edge on the other frame part. In older systems, the blades were riveted into the frame. The increase in the number of blades, however, has made fastening with rivets disadvantageous, because the distance between the rivet holes and the cutting edge increases significantly with each blade. The blades must therefore be processed so that each has a different width, which leads to very wide cutting units, especially in systems with three or more blades. A separate blade geometry is required for each blade position. Another disadvantage of razor blade units produced in this way is that the foam edge and the slide strip are located on different frame parts, so that the parts which determine the skin contact plane must lie within very narrow tolerances with respect to their positioning. Razor blade units with three or more blades are therefore not usually fastened to the frame by rivets any longer.
A razor blade unit in which, during the shaving process, the blades can move up and down in slots against elastic arms in a housing is known from U.S. Pat. No. 4,378,634. Metal clips on the housing hold the blades in the slots and determine the positions of the cutting edges of the blades in the rest position. During production, the blades are first arranged in the housing. Then a U-shaped clip is positioned over the housing and the blades. In the last step, the side pieces of the clip are bent around the bottom area of the housing.
DE 698 28 655 T2 also uses a metal retaining clip to secure the blades which have been attached to the housing. The retaining clip comprises an end piece, which enters into a press-fit with a wedge-shaped section of the housing to make it easier to secure the retaining clip to the housing.
DE 698 16 635 T2 describes a razor unit with a retaining clip of metal to hold the blades. The housing comprises a first lever part, which extends outward over adjacent surface sections located on two sides of the lever part. The retaining clip comprises a first end piece, which has been bent over the first lever part beyond the elasticity limit of the clip. When the first end piece is bent around the first lever part, the lever part is deformed by the exerted pressure, and its height is reduced.
The blades of the razor blade units are usually ground from narrow strips of steel. Because steel is a relatively expensive material, the attempt is made to process strips of the least possible width. To guarantee that the razor blade unit can be rinsed out well, that is, so that the spaces between adjacent blades can be easily rinsed clean, angled blades are usually used in razor systems with three or more blades. The use of angled blades has been known for many years and can be derived from EP 0 064 190, from DE 25 18 499, and from U.S. Pat. No. 4,302,876, for example.
DE 31 27 999 C2 describes a razor with at least one angled blade fastened movably to a main body. Spring fingers, which are supported on the main body, act on the blades. The individual blades assume their desired positioning as a result of the elastic force which the spring fingers exert on the back edges of the blades.
In general, an essential requirement on razor blade units consists in that the cutting edges of the several blades should be positioned precisely with respect to each other and in relation to the skin contact plane. The larger the number of blades in the razor blade unit, the more difficult the positioning. If the cutting edge of one or more blades is not aligned precisely, either there is the danger of injury to the user, or the shaving results are not optimal.